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Thermogravimetry coupled with differential scanning calorimetry (TG–DSC) has been commonly used in the field of conservation of Cultural Heritage for the study of art objects, especially for the characterisation of inorganic matrixes. In recent years, thermal analyses have been applied to the study of organic painting materials. The advantages of performing TG–DSC are linked to the fact that it is micro-destructive technique which does not require any treatment prior the analysis and provide useful information in relatively short time. The aim of this study is to describe the application of TG–DSC on the study of oil binders used in contemporary paints. Even if synthetic binders have become increasingly popular in the 20th century, many contemporary artists still prefer the more traditional media: drying oils. Although the wish of recalling traditional methods, much practical knowledge in paint preparation by mixing drying oil and pigments and in the behaviour of the mixture has been lost. This is mainly due to the different composition of contemporary materials in comparison with the traditional ones and may sometimes lead to different drying properties of the oil paint formulations and consequent problems in the art creation and conservation. For answer to this artistic need and in particular to the difficulties outlined by artists themselves in producing and employing oil paints, unpigmented and pigmented oil films were studied after a week, 1 and 2 years of natural drying under laboratory conditions. Thermal analyses were performed in air flow: the focus of this research was, in fact, to study the thermal and oxidative behaviours of young films for better understanding the very first processes leading to the formation of the film.

The surfaces of Venetian palaces are a testimony to a long history of maintenance. Documents from nineteenth-century restoration projects assign dates and reveal some reasons for treatments explaining, for example, the use of aggressive cleaning and then the addition of pigments so that the newly restored facade did not appear ‘too white’. Restoration during the twenty-first century has presented the opportunity to study the stone surface of three palaces and their stratigraphy. Three types of layers were identified (pollution deposit, silica/wax treatment and corrosion) which overlay the original stone and show distinct elemental signatures. The texture of the outermost deposit showed that the particle size was greatest when it was derived from areas of greatest exposure to the wind compared with calmer sheltered parts. Waxy treatment layers contained strata that probably derived from the brush used to apply the treatment. These treatment layers were warmer in tone than the superficial deposit or...

The structure of historical “cocciopesto” mortars (utilized in Venice and more generally in the Mediterranean area) have been mimicked with samples of phyllosilicate rich (by 58%) clay heated at different temperatures (between 500 and 700 °C) and treated with lime over a 5-month seasoning period in the air (in the presence of CO2) or alternatively under N2 atmosphere (in the absence of CO2). The structural transformations have been detected with 29Si MAS NMR spectroscopy. Heating converts the crystalline Q3 phyllosilicates into the amorphous Q3am phase. The Q3am phase is partially converted by lime in the presence of CO2 into amorphous Q2am inosilicates, while the Q3 phase remains unchanged. In the absence of CO2, lime converts swiftly the Q3am phase (and more slowly the Q3 phase) into the crystalline Q2 inosilicates and Q1 sorosilicates. As the conditions encountered by historical “cocciopesto” mortars during their secular seasoning are better mimicked by clay treated with lime in the air, the hydraulic properties of the former material are temptatively attributed to the presence of the Q2am phase.

Structural studies to determine the earthquake worthiness of Hagia Sophia in Istanbul have proved that the monument's static and dynamic behavior depends very strongly on the mechanical, chemical and microstructural properties of the mortars and bricks used for the masonry. Hence, the classification of the crushed brick/lime mortars under the category of advanced cement-based composites is concluded, explaining the fact that the monument still stands, as well as the very large static deformations which it has undergone, since such mortars have a very long curing period. According to the analysis of the dynamic data, the first three natural frequencies of the building were determined. These results show a decrease of approximately 5–10% in the natural frequencies, as the amplitude of the accelerations increases and returns to their initial values, due to the non-linear nature of the masonry. The above-mentioned behavior allows the structure to absorb energy without affecting irreversibly its material properties. The determination of the mortar properties indicated that they are of considerable mechanical strength and longevity. The dated mortar samples examined proved to be resistant to continuous stresses and strains due to the presence of the amorphous hydraulic formations (CSH), investigated by transmission electron microscopy (TEM) at the crushed-brick powder/binder interfaces and at a sufficient content in the binding matrix, as proved by TG-DTA, which allowed for greater energy absorption without initiations of fractures, let alone the transition of the gel to a higher order of formation. Furthermore, the interpretation of the amorphous nature of the hydraulic formations of the crushed brick/lime mortars is attempted by the experimental validation of real chemical interaction between lime and clay and the characterization of the fundamental structural units of the calcium silicate hydrates, produced by mass spectroscopy.

The facades of the Bank of Greece historic building, mainly consisted of porous stone, gray marble and white pentelic marble, are subjected to an intensive air pollution attack in the center of Athens. A diagnostic study was carried out prior to the cleaning procedures for the weathering evaluation. Weathering appears mainly as black depositions, salt crusts, and oily depositions, due to the heavily polluted urban atmosphere from the nearby traffic. Previous improper cleaning treatment by water spray under high pressure caused detachment of grains and fissuring which were recognized as mechanical abrasion of the surfaces. In this study, a pilot investigation is performed with the intention of evaluating the most appropriate cleaning treatment. Therefore, several cleaning procedures were performed in the laboratory and in situ for the evaluation of methods and products applied on the facades. Both chemical and physical cleaning procedures were applied and they were chosen for their selective action: only water and sepiolite for solvent action, ammonium bicarbonate for exchange action, EDTA for the chemical chelating action and microblasting for physical action were used. In situ non-destructive evaluation was performed by Fiber Optics Microscopy in order to assess the counteractions of each cleaning method to the original surfaces. Digital Image Processing was also used to account for the efficiency of each cleaning method.

This research focuses on the characterization of historical mortars collected from a covered dockyard, called tezone 105, erected in the Arsenal of Venice during the XVI century. The mortars date back to different building phases. A stratigraphical analysis of tezone 105 has proposed a chronology of building interventions. The building phases recognized by the stratigraphical analysis belong to the original structure (XVI century) and to later interventions from XVI to XX century. Mortar samples are investigated by granulometric analysis, infrared spectroscopy (FT-IR), simultaneous thermal analysis (DSC/TG) and X-ray diffraction analysis (XRD) in order to identify the technology peculiar of each building phase. Mortar sampling was carried out on indoor masonry and foundation. Masonry mortars appeared to be characterized by the application of air-hardening binders, whereas foundation mortars were characterized by hydraulic binders.

Rubble masonry mortars are distinct to the masonry mortar joints due to the different construction techniques used and the prerequisites concerning their behavior in the structure. In the present work, physico-chemical and mineralogical examination of rubble masonry mortars is performed on the development of cohesion and adhesion bonds. A working hypothesis on production technology is deduced consequently. Recent collapses of the rubble masonry at several bastions of the knights' period in the Medieval fortifications of Rhodes allow for sampling. Investigations by optical microscopy, scanning electron microscopy, fiber optics microscopy, X-ray diffraction analysis, differential thermogravimetric analysis, porosimetry as well as total soluble salts measurements were performed. Various types of rubble masonry mortars are evidenced and all of them present a very coherent matrix, either ‘cementitious’ or very finely crystallised and compact. From the top to the bottom of the masonry, different microstructural characteristics are observed in the mortar nucleus, indicating different lime-to-aggregates ratios. The microstructural stratification of the cementing material points out different carbonation and drying levels and implies successive supply of water to slake the lime in situ. The evidence of hydraulic components all around the bulk, but not on the outer top of the walls, is of particular interest and proves the in situ slaking of lime as the energy source to activate either hydraulic reactions among lime and clay minerals or the crystallization of portlandite. The high levels of soluble salts measured indicate the mortars' susceptibility to salt decay, specifically when pore size distribution is in favor, as in the case of the modern cement or the pure calcitic mortar, in comparison with the more resistant hydraulic mortars.

The capillary rise effect on brickwork not located along the canals has been studied in previous works in Venice. In the present work, arguments concerning the capillary rise effects on brickwork along the canals are being dealt with. The research program has been developed on walls of different typologies, building materials, historical periods of construction, position and exposure orientation as well as different conditions of maritime traffic. Brick specimens from various points in height and in depth were sampled and underwent physical and chemical examination. In particular, soluble salt concentration, composition and distribution within the wall was determined by Atomic Absorption Spectrophotometry and Ionic Chromatography. Various salts present were identified by FT-IR, while TG-DTA was employed to identify thermal decomposition products. Porosity, as a significant physical parameter for the physico-chemical phenomena, was measured by a mercury porosimeter. The results conclude that the phenomenon of capillary rise is very advanced, due to higher values of soluble salts in comparison with walls not in direct contact with the canals, and mechanical action is increasing the integral porosity.

The study of traditional mortars has recently been attracting considerable attention, in connection with both diagnosis and applications required for restoration. The mortar is only apparently a simple system; in reality the lime is often accompanied by hydraulic components. The inerts often interact with the binder and the technologies used in the application are very diversified. These situations make the study of the mixtures rather complex, as it is difficult to distinguish the neoformation compounds from the older ones. A basic approach is offered by granulometric analysis, allowing separation of the mortar into its components, in which the finer fraction is richer in binder. Some analyses on this fraction ( μ m) were performed to define the nature and quantity of the binder in the mortar. Samples were taken from various sites in Venice and were examined by calcimetry, TG-DTG and FTIR analysis. Moreover the investigation of this fraction by optical microscopy enabled us to distinguish the binder from the inert particles.

The present work focuses on the investigation of mortar joints of historic masonries consisting traditionally of aerial binder and inerts which contain lumps. The presence of lumps, usually white in colour and of various dimensions, was often recorded inside these mixtures and does not appear to be random, as they are rather frequent, These lumps could confer some physicochemical properties to the mixture, that favour the overall compatibility of the system. For this purpose, various samples taken from historic Venetian masonry were examined by TG-DTG and FTIR analysis. Moreover SEM and fibre optical microscope observations were performed. The results indicate mainly the presence of completely carbonated lime and lead us to assume that the lumps arise from technologies based on the non-seasoning of the lime.

Publisher Summary This chapter describes the method for the study of the effects of condensation on limestone surfaces. The results of condensation characterization in a lake environment indicate rather low pH values, in various cases lower than 6. The bicarbonate ion contents correspond to the pH. The ion concentration regarded as representative of both condensation and its effect on stone surfaces was evaluated. The evaluations were recorded by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Initial results indicate effects related to the direct action of acidic substances, particularly dissolved carbon dioxide (CO2), leading to the recrystallization of calcite into smaller crystals. The results obtained from the condensation analysis in the Venice area indicate that it contains significant amounts of HCO3- ions, while other ions generally included in the “polluting” category (SO2 and NOx) are not present in particularly high concentrations. On the other hand, chloride ions (CI-) and sodium ions (Na+), which are characteristics of sea aerosol, were detected. Thus, the determination of pH is very important in indicating the intensity of the interaction between condensation and stone.

Structural studies to determine the earthquake worthiness of Hagia Sophia in Istanbul have proved that the monument's static and dynamic behavior depends very strongly on the mechanical and chemical properties of these mortars and bricks used in its masonry. So, the cementrtious nature of the mortars not only explains the fact that the monument still stands but also the very large static deformations which it has undergone, since such mortars have a very long curig period from one to two years. According to the analysis of the dynamic data, the strong motion data from a 4.8R magnitude earthquake about 120 Km south of the building was used to determine the first three natural frequencies of the building. These results show a decrease of about 5–10% in the natural frequencies, as the amplitude of the accelerations increases and returns to their initial values, due to the non-linear nature of the masonry. The above mentioned behavior allows the structure to absorb energy without effecting its material properties, irreversibly. The properties of the mortars and bricks leaded to an extensive study, employing several experimental techniques (FOM, OM, XRD, SEM, TEM, TG/DTA). The results indicated mortars with considerable mechanical strength along with longevity. The model used proved to be resistant to the environmental pollution and to the presence of sah, while the gel phase as binder allows for greater energy absorption and the compatibility of the mortar to the original ones allows continuous stresses and strains. Hence, the recreation of the Hagia Sophia is attempted through a reverse engineering approach to simulate the historical mortars.

In the present study the possible chemical interactions among the constituents of historical walls have been investigated. In Venice but also in the whole mediterranean area the “cocciopesto” (constituted of powder and brick fragments which traditionally confer hydraulic properties to the mortar) has been widely employed both for mortars and the so called “marmorino” plasters. The work has been developed by examing the brick-mortar interaction on historical buildings in Venice. The samples were chemically analysed through XPS and XPSImaging techniques in order to ascertain the chemical composition of the interface layers. The results clearly indicate that a true chemico-physical interaction between brick and lime is present in the historical materials. A calcium carbonate accumulation has been observed at the brickmortar interface.

The aim of the present work is to compare the protective effect of solvent and water dispersed products on marble, Lecce and Istria stones. This choice is justified by the need of products effective also from the ecological and toxicological point of view. To obtain these informations two tests have been chosen: contact angle and water absorption. The contact angle may, in theory, be considered a measure of the water repellency, since complete wetting implies a contact angle of 0° and absolutely no wetting an angle of 180°. This does not apply to the water absorption by capillarity test because the absorption variation may be caused by either the water repellency action of the treatments or by the pore filling. However this test may give practical information about the general effect of the treatments. Moreover, the effect of treatments on permeability was investigated by vapour permeability test. Protective effect was studied after application of the products and at various stages of artificial weathering.

Different decay mechanisms, according to the exposure to rain actions, have been identified on a series of Istria stone samples derived from the Venetian buildings. Enquiries have been carried out on these samples by means of porosity measurements and chemical analysis in depth. In order to identify the decay mechanisms and their.kinetics, simulation tests have been,performed on exposed samples of Istria stone for a period of 19 months. These specimens have been analysed by several techniques in order to verify the chemical dissolution of limestone provoked by the rain action. The initial chemical attack on the exposed samples has been pointed out by XPS and RBS micro-analytical techniques.

The present study is directed to summarize several studies carried out in the recent past on stone decay processes taking place in the lagoon environment of Venice. The behaviour of the main types of stones used in Venetian buildings has been considered.Istrian stone, Verona red stone and Carrara marble were studied.The knowledge of the porosity and of the pore size distribution can contribute to clarify the physical transformation of decayed materials.The research determined the morphology of stone decay processes for the different types of stone.As far as the morphology of deterioration is concerned, there are two main types of decay which depend on the intrinsic properties of the stone: chemical-mineralogical composition and texture-structure.

The hydrido-1,3-di- p -tolyltriazenido complex of platinum(II) trans -[Pt(PPh 3 ) 2 H( p -CH 3 C 6 H 4 NNNC 6 H 4 CH 3 - p )] reacts with CO, 2,6-Me 2 C 6 H 3 NC, PPh 3 and PhCCPh under mild conditions to yield platinum(0) complexes by reductive elimination of 1,3-di- p -tolyltriazene.

In the present study several cleaning procedures were taken into account: microblasting, ammonium carbonate, EDTA, etc. The various cleaning procedures were applied to Venetian Istria stone manufacture. The performance evaluation of the various procedures employed was accomplished by measuring the following significant parameters, before and after treatment: colour change through the CIELab method, surface morphology through a fiber optical microscope (MFO) and analysis of the different chemical action of the employed procedures.

The mortars and `cocciopesto' plasters were largely used in the historic buildings, as waterproof coverings and in the preparation of mortars, especially in horizontal structures. In recent years, the necessity of restoration interventions with materials which are compatible with the masonry structure requires a detailed study on these materials. In this study, the composition of a significative number of mortars of the Byzantine period in the Hagia Sophia Basilica are investigated. They were made of `cocciopesto' (crushed ceramic) and probably have a bearing function in the masonry structure. The samples are examined by particle size, infrared spectroscopy (FT-IR) and thermogravimetric analyses (TG-DTG), both on the total sample and on the finer fraction (